A quick review of tens and ones place values. Understanding how numbers are built is the first step to taking them apart with subtraction! This is essential knowledge before learning to regroup.
What are the two 'places' in a two-digit number like \(47\)?
The tens place (where the \(4\) is) and the ones place (where the \(7\) is).
In the number \(83\), what does the digit \(8\) represent?
It represents \(8\) tens, which has a value of \(80\).
In the number \(83\), what does the digit \(3\) represent?
It represents \(3\) ones, which has a value of \(3\).
How many ones are equal to one ten?
$$ 1 \text{ ten} = 10 \text{ ones} $$
How would you write the number \(52\) by breaking it into tens and ones?
\(5\) tens and \(2\) ones.
If you have \(4\) tens and \(15\) ones, what number do you have?
You have the number \(55\). (\(4\) tens = \(40\), plus \(15\) ones gives you \(55\)).
When you write a subtraction problem, why is it important to line up the ones place and the tens place?
So you subtract the ones from the ones and the tens from the tens correctly. It keeps your numbers organized. $$\begin{array}{rr}
& 34 \\
- & 17
\end{array}$$
What is the value of the digit \(9\) in the number \(91\)?
